Oregon College Students Consume More Cannabis Following Recreational Legalization: Study

Cannabis use is up among college students in Oregon following recreational legalization of the plant, according to a new study published in the journal Addiction.

Using information collected in the Healthy Minds Study – a national survey by the University of Michigan on college students’ wellbeing – researchers from Oregon State University compared cannabis consumption among college students before and after legalization.

They found that usage increased at several post-secondary schools across the country, but it rose more dramatically at the Oregon school. No institutions were identified in the study.

"It does appear that legalization is having an effect on usage, but there is some nuance to the findings that warrant further investigation," said lead author David Kerr of the School of Psychological Science in OSU's College of Liberal Arts.

"We found that overall, at schools in different parts of the country, there's been an increase in marijuana use among college students, so we can't attribute that increase to legalization alone."

The study – by co-authors Harold Bae and Sandi Phibbs of OSU's College of Public Health and Human Sciences and Adam Kern of the University of Michigan – is the first to look at cannabis use patterns following recreational legalization in Oregon, and the first to analyze the impact of any state’s legalization on college students. Oregon’s recreational cannabis law took effect in 2015.

"It's an important current issue and even the most basic effects have not been studied yet, especially in Oregon," said Kerr. "There are a lot of open questions about how legalization might affect new users, existing users and use of other substances."

Using data from a large public university in Oregon and six other universities across the country where recreational cannabis use is not legal, researchers looked at frequency of heavy alcohol and cigarette use along with cannabis consumption.

"It's likely that the rise in marijuana use across the country is tied in part to liberalization of attitudes about the drug as more states legalize it, for recreational or medical purposes or both," Kerr said.

"So legalization both reflects changing attitudes and may influence them even outside of states where the drug is legal."

Cannabis use was found to be generally higher among male students; those living in Greek or off-campus housing; those not identifying as heterosexual; and those attending smaller, private institutions.

Researchers also found that students at the Oregon university who reported binge drinking were 73 percent more likely to also report cannabis use – compared to similar peers in states where cannabis is still illegal.

"We think this tells us more about the people who binge drink than about the effects of alcohol itself," Kerr said.

"Those who binge drink may be more open to marijuana use if it is easy to access, whereas those who avoid alcohol for cultural or lifestyle reasons might avoid marijuana regardless of its legal status."

It was also revealed that Oregon students under the age of 21 showed higher rates of cannabis use than those over 21.

"This was a big surprise to us, because legalization of use is actually having an impact on illegal use," said Bae, a statistician with the study.

Kerr said more research is needed before the harms or benefits of legalization on young people can be quantified.

"Americans are conducting a big experiment with marijuana," Kerr said. "We need science to tell us what the results of it are."